Description:
------------
When file_get_contents() is used in combination with stream_context_create() not all wrapper options are taken into consideration.

Tested PHP versions on Linux:
5.1.5 - not working
5.1.1 - working
5.0.4 - working

This bug doesn't seems to appear on Windows platforms:
5.1.5 - working


Reproduce code:
---------------
<?php

// this code will perform a POST request to a URL with this code:
// print_r($_POST)

echo file_get_contents("http://www.example.com/info.php",null,stream_context_create(array(
        'http' => array(
                'method' => 'POST',
                'content' => 'cmd=_notify-validate',
                'header' => 'Content-Type: application/x-www-form-urlencoded',
        )
)));

?>

Expected result:
----------------
Array
(
    [cmd] => _notify-validate
)


The meta information:
CONTENT_LENGTH: 20
REQUEST_METHOD: POST
CONTENT_TYPE: application/x-www-form-urlencoded


Actual result:
--------------
Array
(
)


The meta information:
HTTP_USER_AGENT: PHP/5.1.5 <-- this didnt't appear anywhere else
REQUEST_METHOD: GET
CONTENT_TYPE: application/x-www-form-urlencoded